Zemina

From http://www.hardcoregaming101.net/korea/part1/company-zemina.htm:
Born out of the country's thriving bootleg industry, Zemina (the name can be read as "It's fun!" in Korean) became one of the first companies to also steadily release domestically programmed games. Most of these were still ports or reinterpretation of known games, like Super Mario Bros. or Tetris. However, in later years, their games became more and more independent of their archetypes, but they never emancipated themselves completely from other companies' material. The following game introductions are confined to titles where it can be confirmed that their role consisted of more than just hacking their "copyright" into the game.
While Zemina were a MSX developer first and foremost, most of their titles got also converted to the Samsung Gam*Boy/Master System. They even released one game under official license, Konami's Nemesis 3, as Salamander 2, all the while still selling pirate copies of the Japanese company's pre-1987 games. Like many companies at that time, their endeavors weren't limited to software products, but they also manufactured a number of accessories. Their catalogue included cartridge port divider modules, a MSX music cartridge, RAM expansions and a Famicom-to-MSX converter.
As it seems, at about 1989 Zemina stopped being an independent company by itself and became owned by an enterprise called Saehan Sangsa. Their games were developed by at least three different teams: Lead developer Kim Eulsuk and Koo Eunjoong were responsible for Brother Adventure and the Super Boy series, Lee Kyuhwan and Lee Sanghun did Double Dragon and The Three Dragon Story, and team MBITM under Jeong Chanyong finally created the Bubble Bobble ports and Micro Xevious. There's a number of games left that don't contain any credits, though.
In July 1990, Saehan Sangsa first exported a number of games, ram slot expansions and music add-ons in value of reportedly US$70,000 total to a Netherlands-based distributor called MSX Centrum (MyCom 09/91 News). Later also the MSX Club Gouda imported Korean cartridges, mostly by Zemina. The games were sold in humble quantities in Europe, though.
There are literally dozens of businesses that go by the name Saehan Sangsa in Korea, so it is quite impossible to secure any more information on the mother company. In 1992, Zemina's internal programmers left to form the company Open, and there have been no more Zemina games since then, so Saehan Sangsa either went out of business or quit putting out games by that time.
Key People:
Jeong Hyeonsu: President
Kim Eulsuk: Head of Development Section